Officials are probing how a 51-year-old highway bridge came to collapse in the Italian port city of Genoa yesterday, killing at least 26 people and injuring 16 others as it sent dozens of vehicles tumbling into a heap of concrete and twisted steel.

200 calls for help as NSW gets drenched

The NSW State Emergency Service (SES) has received over 200 calls for help along the state's coastline but says the worst of the weekend's wet has probably passed.

A severe weather warning remains in place for Sydney, the Hunter, the Illawarra, the mid-north coast and the south coast, but conditions are expected to ease.

The Bureau of Meteorology warned at 11am (AEST) on Saturday of damaging winds and surf and heavy showers for southern and central parts of the NSW coast.

SES spokesman Phil Campbell told AAP that by mid-afternoon crews had been called to just over 200 homes, mainly in the Illawarra, along the south coast and in Sydney's eastern suburbs.

Leaking roofs had been the biggest issue but there had also been some localised flash flooding, he said.

Conditions are expected to ease through Saturday and early on Sunday as the weather system moves north, but the Bureau of Meteorology has warned that strong to gale force winds could continue to bring heavy showers and big surf to coastal areas.

Kincumber on the central coast was one of the state's wettest spots, recording 58 millimetres of rain over nearly six hours between 9am (AEST) and 3pm on Saturday.

Bureau of Meteorology figures showed Sydney's observation station got 32 millimetres, while 51 millimetres fell on Wahroonga in the city's north and 63 millimetres fell at Ulladulla on the state's south coast.